Fritz Lang's frighteningly suspenseful 1931 film was his first using sound, and with a new digital restoration, it holds up brilliantly.

Whether you're seeing it for the first time or revisiting an old favorite, Fritz Lang's "M" in its new digital restoration should not be missed. Few films are gripping and effective 82 years after their original release, but this one surely is.

Looking impeccable in its fresh digital sheen and graced with improved subtitles, this most-complete-ever version of "M" clocks in at 111 minutes. That's considerably longer than earlier prints of Lang's taut masterpiece of a city obsessed with the hunt for a frightening child murderer.

Yet as played by Peter Lorre in both his first lead role and the part that made him an international star, murderer Hans Beckert is as pitiable as he is terrifying, a heavy-lidded, unhappy man with a pudgy face and a deceptively diffident manner.

Though Lang was already a major German director with more than a dozen films (including the landmark "Metropolis") to his credit by 1931, "M" was his first sound film. So he took special care with all its elements, from cinematographer Fritz Arno Wagner's inventive camera angles to an unusual sound design that included calculated periods of complete silence.

That calculation is also evident in the measured, inexorable way screenwriter Thea von Harbou, Lang's wife at the time, lets the story unfold, giving equal weight to suspense and surprise.

While the murderer's identity is known to us almost at once, one of Lang's many shrewd decisions is not letting his full face be revealed to the camera quite so fast.

"M" opens with young girl coming home from school for lunch. She innocently bounces a ball against a huge poster offering a 10,000-mark reward for the murderer, who has already killed half a dozen children. Suddenly, the shadow of Beckert's profile chillingly falls against the poster as he quietly asks the little girl her name.

One of the most compelling aspects of "M" viewed from the vantage point of today is its understanding of mob psychology and mob violence in a way that seems to prefigure the Nazi regime that was soon to emerge. Fear is so prevalent in this unnamed city that neighbor turns against neighbor and the thin veneer of civilization is all but ripped away.

Meanwhile the police, rigorous and scientific though they are, are completely baffled by a murderer who seems totally normal except for those few minutes when madness takes over. Frustrated, they end up raiding local criminal establishments almost every night, cutting into profits and leading to the decision that kicks "M" into its highest gear.

In a scene that is intercut with a meeting of the city's law-and-order establishment, the leaders of the underworld, chaired by the black-leather-jacketed Schränker (Gustaf Gründgens), decide they have no choice but tocatch the murderer themselves.

To accomplish this task, the criminal elite enlists the help of the metropolis' highly organized beggars (this is Germany, where everything seems to be highly organized) to watch every street in the city and report on suspicious activity.

Two key elements figure in the final hunt for the murderer. At one point, a chalk-mark "M" is placed on Beckert's back (the action that gives the film its title), and a blind balloon-seller recognizes the killer's habit of whistling "In the Hall of the Mountain King" from Edvard Grieg's "Peer Gynt Suite." (It was Lang himself and not Lorre who ended up doing the whistling, we hear.)

Though sections of this film prefer silence to sound, the most unforgettable part of "M" comes with its final speeches both coldly condemning the murderer's actions and pleading for mercy. Most moving of all is Lorre's tour de force self-defense, the words of a man incapable of escaping from himself. "Don't want to, must; don't want to, must," he says over and over, the desperation growing in his voice. It's a moment that is, like the rest of this remarkable film, hard to get out of your mind.